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101.
Functional tyrosine kinase inhibitor profiling: a generally applicable method points to a novel role of platelet-derived growth factor receptor-beta in tuberous sclerosis 总被引:1,自引:0,他引:1 下载免费PDF全文
Arbiser JL Govindarajan B Bai X Onda H Kazlauskas A Lim SD Amin MB Claesson-Welsh L 《The American journal of pathology》2002,161(3):781-786
A ubiquitous herpesvirus that establishes life-long infection, the Epstein-Barr virus (EBV) has yielded little insight into how a single agent in general accord with its host can produce diverse pathologies ranging from oral hairy leukoplakia to nasopharyngeal carcinoma, from infectious mononucleosis to Hodgkin's disease (HD) and Burkitt's lymphoma. Its pathogenesis is further confounded by the less than total association of virus with histologically similar tumors. In other viral systems, defective (interfering) viral genomes are known to modulate outcome of infection, with either ameliorating or intensifying effects on disease processes initiated by prototype strains. To ascertain whether defective EBV genomes are present in HD, we examined paraffin-embedded tissue from 56 HD cases whose EBV status was first determined by cytohybridization for nonpolyadenylated EBV RNAs (EBERs). Using both standard polymerase chain reaction (PCR) and PCR in situ hybridization, we successfully amplified sequences that span abnormally juxtaposed BamHI W and Z fragments characteristic of defective heterogeneous (het) EBV DNA from 10 of 32 (31%) EBER-positive tumors. Of 24 EBER-negative HD, 8 yielded PCR products indicating presence of het EBV DNA. Two of these contained defective EBV in the apparent absence of the prototype virus. Of the 42 tumors analyzed for defective EBV by both PCR techniques, there was concordance of results in 38 (90%). Detection of defective EBV genomes with the potential to disrupt viral gene regulation suggests one mechanism for pathogenic diversity that may also account for loss of prototypic EBV from individual tumor cells. 相似文献
102.
Converging collimation increases the geometric efficiency for imaging small organs, such as the heart, but also increases the difficulty of correcting for the physical effects of attenuation, geometric response and scatter in SPECT. In this paper, 3D first-order Compton scatter in non-uniform scattering media is modelled by using an efficient slice by-slice incremental blurring technique in both parallel and converging beam SPECT. The scatter projections are generated by first forming an effective scatter source image (ESSI), then forward-projecting the ESSI. The Compton scatter cross section described by the Klein-Nishina formula is used to obtain spatial scatter response functions (SSRFs) of scattering slices which are parallel to the detector surface. Two SSRFs of neighbouring scattering slices are used to compute two small orthogonal 1D blurring kernels used for the incremental blurring from the slice which is further from the detector surface to the slice which is closer to the detector surface. First-order Compton scatter point response functions (SPRFs) obtained using the proposed model agree well with those of Monte Carlo (MC) simulations for both parallel and fan beam SPECT. Image reconstruction in fan beam SPECT MC simulation studies shows increased left ventricle myocardium-to-chamber contrast (LV contrast) and slightly improved image resolution when performing scatter compensation using the proposed model. Physical torso phantom fan beam SPECT experiments show increased myocardial uniformity and image resolution as well as increased LV contrast. The proposed method efficiently models the 3D first-order Compton scatter effect in parallel and converging beam SPECT. 相似文献
103.
脑缺血再灌流对大鼠海马FOS蛋白的诱导及电针对其的影响 总被引:5,自引:0,他引:5
目的 探讨脑缺血再灌流后电针对大鼠海马FOS蛋白表达的影响。方法 采用夹闭大鼠双侧颈总动脉造成的脑缺血再灌流损伤模型 ,电针“百会”、“风池”、“大钟”及“足三里”穴 ,频率 2~ 2 0Hz,强度以肌肉轻微抖动为准 ,持续 30min ,4h后观察海马FOS蛋白的表达。结果 电针能明显加强脑缺血再灌流后海马各区FOS蛋白的表达。结论 缺血再灌流可诱导海马FOS蛋白的显著表达 ;电针信息对缺血后海马神经元的功能可能会有影响。 相似文献
104.
目的建立自动化、高通量、准确快速检测缺失型α-地中海贫血基因型的技术。方法应用SYBR-Green1进行两个实时荧光聚合酶链反应(real-time fluorescence polymerase chain reaction with SYBR-Green1,SYBR-PCR),检测左缺(-α4.2)、右缺(-α3.7)等位基因,同时进行融解曲线(dissociation curve,DC)和Tm(melting temperature)值分析。PCR产物重组到pCR2.1,重组子梯度稀释作为模板检测灵敏度,确定两种等位基因型(-α4.2,-α3.7)的检测下限,并对110份DNA样品进行检测。结果检测-α4.2和-α3.7的PCR产物长度分别为1.65kb、1.9kb,Tm分别为(81.5±0.5)℃、(82.5±0.5)℃,检测下限分别为9×102个拷贝、4.3×102个拷贝。该检测技术的灵敏度较常规PCR结合琼脂糖凝胶电泳法高10倍。结论SYBR-Green1实时荧光PCR结合融解曲线分析及Tm分析可以灵敏、准确地检测-α4.2、-α3.7、αα(包括αTα)及--SEA4种等位基因,从而为各种缺失型α-地中海贫血做出基因诊断。该技术具有自动化程度高,不需荧光标记探针,成本低,易质控,防污染,高通量等优点,适于临床推广应用。 相似文献
105.
Differentiation of mycobacterial species by PCR-restriction analysis of DNA (342 base pairs) of the RNA polymerase gene (rpoB) 总被引:2,自引:0,他引:2 下载免费PDF全文
Kim BJ Lee KH Park BN Kim SJ Bai GH Kim SJ Kook YH 《Journal of clinical microbiology》2001,39(6):2102-2109
PCR amplification-restriction analysis (PRA) of rpoB DNA (342 bp), which comprises the Rif(r) region, was used for the differential identification of 49 mycobacteria. The DNA had been used previously for the identification of mycobacterial species by comparative sequence analysis (B. J. Kim et al., J. Clin. Microbiol. 37:1714-1720, 1999). Digestion with four restriction enzymes (HaeIII, HindII, MvaI, and AccII), which were selected on the basis of rpoB DNA sequences, generated distinctive PRA patterns that allowed not only the reference strains but also the clinical isolates of mycobacteria to be distinguished. Both rapidly and slowly growing mycobacteria were distinctly differentiated by HaeIII digestion of the amplified rpoB DNA. By HindII digestion the Mycobacterium tuberculosis complex was distinguished from the other mycobacteria. Furthermore, six subspecies of Mycobacterium kansasii (subspecies I to VI) as well as the closely related Mycobacterium gastri, and other closely related species, were distinguished by simultaneous digestion of MvaI and AccII. According to the rpoB PRA scheme, 240 strains of clinical isolates could be identified. It was also possible to detect and identify M. tuberculosis directly from sputa and bronchoalveolar lavage specimens. These results suggest that PRA of rpoB DNA is a simple and feasible method not only for the differentiation of culture isolates but also for the rapid detection and identification of pathogenic mycobacteria in primary clinical specimens. 相似文献
106.
Liu JQ; Bai XF; Shi FD; Xiao BG; Li HL; Levi M; Mustafa M; Wahren B; Link H 《International immunology》1998,10(8):1139-1148
Induction of mucosal tolerance by inhalation of soluble peptides with
defined T cell epitopes is receiving much attention as a means of
specifically down-regulating pathogenic T cell reactivities in autoimmune
and allergic disorders. Experimental autoimmune encephalomyelitis (EAE)
induced in the Lewis rat by immunization with myelin basic protein (MBP)
and Freund's adjuvant (CFA) is mediated by CD4+ T cells specific for the
MBP amino acid sequences 68-86 and 87-99. To further define the principles
of nasal tolerance induction, we generated three different MBP peptides
(MBP 68-86, 87-99 and the non- encephalitogenic peptide 110-128), and
evaluated whether their nasal administration on day -11, -10, -9, -8 and -7
prior to immunization with guinea pig MBP (gp-MBP) + CFA confers protection
to Lewis rat EAE. Protection was achieved with the encephalitogenic
peptides MBP 68-86 and 87-99, MBP 68-86 being more potent, but not with MBP
110-128. Neither MBP 68-86 nor 87-99 at doses used conferred complete
protection to gp-MBP-induced EAE. In contrast, nasal administration of a
mixture of MBP 68-86 and 87-99 completely blocked gp-MBP-induced EAE even
at lower dosage compared to that being used for individual peptides. Rats
tolerized with MBP 68-86 + 87-99 nasally showed decreased T cell responses
to MBP reflected by lymphocyte proliferation and IFN-gamma ELISPOT assays.
Rats tolerized with MBP 68-86 + 87-99 also had abrogated MBP-reactive
IFN-gamma and tumor necrosis factor-alpha mRNA expression in lymph node
cells compared to rats receiving MBP 110-128 nasally, while similar low
levels of MBP-reactive transforming growth factor-beta and IL-4 mRNA
expressing cells were observed in the two groups. Nasal administration of
MBP 68-86 + 87-99 only slightly inhibited guinea pig spinal cord
homogenate-induced EAE, and passive transfer of spleen mononuclear cells
from MBP 68-86 + 87-99-tolerized rats did not protect naive rats from EAE.
Finally, we show that nasal administration of MBP 68-86 + 87-99 can reverse
ongoing EAE induced with gp-MBP, although higher doses are required
compared to the dosage needed for prevention. In conclusion, nasal
administration of encephalitogenic MBP peptides can induce antigen-specific
T cell tolerance and confer incomplete protection to gp-MBP-induced EAE,
and MBP 68-86 and 87-99 have synergistic effects. Non-regulatory mechanisms
are proposed to be responsible for tolerance development after nasal
peptide administration.
相似文献
107.
Cytogenetic and molecular cytogenetic studies of a case of interstitial deletion of proximal 15q 总被引:3,自引:0,他引:3
Vijay Tonk Herman E. Wyandt Peter Osella James Skare Bai Lin Wu Bassem Haddad Aubrey Milunsky 《Clinical genetics》1995,48(3):151-155
A 4-month-old child with multiple anomalies was determined to have an interstitial deletion of chromosome 15, i.e., del(15) (q12q14). The deletion appears not to be a typical deletion of 15q12 such as seen in Angelman and Prader-Willi syndromes, but appears to be more distal, involving either loss of all of 15q12 and part of 15q14, or part of 15q12 and most of 15q14. In either case, 15q13 is missing. Fluorescent in situ hybridization with probes for 15 centromere (D15Z), pericentromeric satellite sequences (D15Z1), and chromosome 15 painting probes shows the deleted chromosome to involve only 15 and no other acrocentric chromosome. Hybridization with probes for the AS and PWS loci (D15S11 and GABAB3, Oncor) show both sites to be intact in the deleted 15. The case is compared with two other reports with overlapping interstitial deletions of proximal 15q, neither of which shows typical features of Angelman or Prader-Willi syndromes. 相似文献
108.
深入探讨长骨骨折愈合塑形阶段的力学机理,采用骨表面再造理论与有限元结合的方法。我们选取用应变能密度作为力学激励的骨表面再造理论,有限元分析采用三维的空间模型,利用我们编制的长骨表面再造系统“BRSS97”对长骨骨折愈合塑形阶段的三种类型:外骨痂型、骨内缺损型和骨外缺损型的力学机理进行研究。结果表明:骨痂可以完全吸收,骨缺损可以恢复,三种情况下骨均可以恢复到正常状态。由此说明长骨骨折愈合塑形过程就是骨材料对力学激励的适应过程。 相似文献
109.
The generation and characterization of a cell line derived from a sporadic renal angiomyolipoma: use of telomerase to obtain stable populations of cells from benign neoplasms 下载免费PDF全文
Arbiser JL Yeung R Weiss SW Arbiser ZK Amin MB Cohen C Frank D Mahajan S Herron GS Yang J Onda H Zhang HB Bai X Uhlmann E Loehr A Northrup H Au P Davis I Fisher DE Gutmann DH 《The American journal of pathology》2001,159(2):483-491
Angiomyolipomas are benign tumors of the kidney derived from putative perivascular epithelioid cells, that may undergo differentiation into cells with features of melanocytes, smooth muscle, and fat. To gain further insight into angiomyolipomas, we have generated the first human angiomyolipoma cell line by sequential introduction of SV40 large T antigen and human telomerase into human angiomyolipoma cells. These cells show phenotypic characteristics of angiomyolipomas, namely differentiation markers of smooth muscle (smooth muscle actin), adipose tissue (peroxisome proliferator-activator receptor gamma, PPARgamma), and melanocytes (microophthalmia, MITF), thus demonstrating that a single cell type can exhibit all of these phenotypes. These cells should serve as a valuable tool to elucidate signal transduction pathways underlying renal angiomyolipomas. 相似文献
110.
慢性乙肝患者NK,ADCC活性及其对IFN—α,IFN—γ的反应 总被引:1,自引:0,他引:1
本文用Hela细胞乳酸脱氢酶释放法测定了42例慢性乙肝病人外周血NK、ADCC活性及其对IFN-α100U/ml、500U/ml及IFN-γ500U/ml预处理4小时后的反应。结果显示,病人PBL NK,ADCC活性与正常对照有显著差别,经IFNs处理后,其NK或/和ADCC活性均有不同程度的升高反应,从而提示了IFNs在慢性肝病治疗中的重要作用。 相似文献